<div>
  <div>
    <p>你选择的是:</p>
    <span style="margin-left: 10px" *ngFor="let subitem of selectedsubitems">{{subitem.name}}</span>
  </div>
  <div style="display: inline-block" *ngFor="let item of items">
    <button (click)="toggleItem(item)">{{item.name}}</button>
  </div>
  <ul *ngIf="item">
    <li *ngFor="let subitem of item.subitems">
      <button (click)="selectSubitem(subitem)">{{subitem.name}}</button>
    </li>
  </ul>
</div>
